Whether the N.C.O. was in earnest, or merely speaking sarcastically of the Hun machine, Daventry could not determine. His attention was centred upon the darting form of a possible antagonist, who, as yet, was ignorant of the British biplane's presence. The Boche machine was remarkable for the unusual appearance of its wings, or rather non-appearance, for they were made of some sort of transparent fabric that rendered them almost invisible. It was only when the aeroplane banked steeply as she hovered over her intended victim that the rays of the setting sun, glinting on the tilted planes, revealed the presence of the V-shaped wings. Even the black cross was absent, as far as the planes were concerned, although they were painted on the top and sides of the fuselage. The elongated body was fancifully decorated in various colours, the whole resembling a freak machine that might, or might not, prove to be a tough customer. "Wonder if it's Biggs's old pal, Count von Peilfell?" thought Derek. "It's not a seaplane, and the guy is a jolly long way from his base." A thousand feet--five hundred--three hundred. "Let him have it," signalled Derek. The staccato of the Lewis guns mingled with the roar of the motors. Apparently taken completely by surprise, the Hun side-slipped, spun on one wing for several seconds, and then burst into a furnace of smoke and flame. Boldly into the trailing smoke plunged GV 7, keenly in pursuit of the crippled and falling Hun. Half-blinded by the smoke, and choking from the pungent fumes, Derek held on, until a rapid glance at the altitude-gauge showed him that he was but a few feet above the sea. Like a meteor, the British battleplane flattened out, and, emerging from the smoke, began to encircle the fiercely-burning wreckage on the sea. It was not until several minutes had elapsed that the vapour cleared, and Derek realized that he had been badly tricked. The Hun, in diving, had thrown out a novel kind of smoke-bomb, and, surmising that the British biplane would dive in pursuit, the German had climbed to a terrific height, unnoticed by his too eager and credulous antagonist. "We've been on a dud trail," muttered Derek disgustedly, and, glancing aloft, he saw the faint outlines of the Boche machine, looking much like a tadpole, scurrying home at a rapid pace. The advantage of altitude, and the intervening distance, rendered pursuit impracticable, and, reluctantly, Daventry had to recognize tactical defeat. He had, however, saved the tramp steamer from destruction, and, since his orders were definite, he now had no option but to resume his flight for the battle-front. Nevertheless the wireless operator was busily employed reporting the presence and direction of a Hun to the aerial-patrol off Dunkirk, and, with luck, the strong Allied Air Squadron ought to be able to intercept the returning raider.